Display device

ABSTRACT

A display device includes a rollable display panel having two surfaces opposed to each other, and a heat dissipation sheet disposed on one of the two surfaces of the display panel and rollable together with the rollable display panel. The heat dissipation sheet has a thermal conductivity greater than 200 W/mK.

BACKGROUND OF THE DISCLOSURE 1. Field of the Disclosure

The present disclosure generally relates to an electronic device, inparticular to a rollable electronic device.

2. Description of the Prior Art

In recent years, an electronic device or a deformable electronic devicehas become one of the focuses of the new generation of the electronictechnology. Therefore, the demands for a flexible display device whichmay be incorporated into an electronic device have also been increasingaccordingly, such as a rollable display device.

When the battery system board in the rollable display device is working,it generates heat and becomes a heat source. If the heat generated bythe battery system board is not quickly dissipated due to the structuraldesign, the resultantly formed hot spot may affect heat-sensitivecomponents and increase the probability of display abnormalities,thereby reducing the reliability of the display device. Becauseconsumers have higher and higher requirements for flexible displaydevices, it is one of the important issues for manufacturers to developdisplay devices of higher reliability.

SUMMARY OF THE DISCLOSURE

In view of this, the present disclosure proposes a rollable displaydevice with a novel thermal conductive structure. The novel thermalconductive structure may improve the thermal conductivity of therollable display device, or may increase the reliability of the rollabledisplay device.

According to some embodiments of the present disclosure, there isprovided a display device including a rollable display panel and a heatdissipation sheet. The rollable display panel has two surfaces opposedto each other. The heat dissipation sheet is disposed on one of the twosurfaces of the display panel. The heat dissipation sheet is rollabletogether with the rollable display panel. The heat dissipation sheet hasa thermal conductivity greater than 200 W/mK.

According to the rollable display device of the embodiments of thepresent disclosure, by adjusting the shapes, structures and/or thermalconductivity of the heat dissipation sheet, the heat generated by theheat source in the rollable display device may be uniformly dispersed,thereby reducing the temperature of the hot spot. In such a way, theheat dissipation quality of the rollable display device may be improved,or the reliability of the rollable display device may be enhanced.

These and other objectives of the present disclosure will no doubtbecome obvious to those of ordinary skill in the art after reading thefollowing detailed description of the embodiment that is illustrated inthe various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the display device according to thefirst embodiment of the present disclosure in an unrolled state or apartially rolled state.

FIG. 2 is a schematic top view of the display device according to thefirst embodiment of the present disclosure after being fully unrolled.

FIG. 3 is a schematic side view corresponding to FIG. 2 .

FIG. 4 is a schematic side view of a variant embodiment corresponding toFIG. 2 .

FIG. 5 is a schematic diagram of the display device in a partiallyrolled state according to the second embodiment of the presentdisclosure.

FIG. 6 is a schematic side view of an implementation corresponding toFIG. 2 .

FIG. 7 is a schematic side view of another variant implementationcorresponding to FIG. 2 .

FIG. 8 is a schematic side view of another variant implementationcorresponding to FIG. 2 .

FIG. 9 is a schematic bottom view according to an implementation of thepresent disclosure.

FIG. 10 is a schematic bottom view according to an implementation of thepresent disclosure.

FIG. 11 is a schematic bottom view according to an implementation of thepresent disclosure.

FIG. 12 illustrates a schematic side view according to a variantimplementation of the heat dissipation sheet of the present disclosure.

FIG. 13 illustrates a schematic side view according to a variantimplementation of the heat dissipation sheet of the present disclosure.

FIG. 14 illustrates a schematic side view according to a variantimplementation of the heat dissipation sheet of the present disclosure.

FIG. 15 is a schematic side view of the display device according to thethird embodiment of the present disclosure.

FIG. 16 is a schematic diagram of the display device in an unrolledstate according to the fourth embodiment of the present disclosure.

FIG. 17 is a schematic diagram of a variant embodiment of the displaydevice according to the fourth embodiment of the present disclosure.

FIG. 18 is a schematic diagram of another variant embodiment of thedisplay device according to the fourth embodiment of the presentdisclosure.

FIG. 19 is a schematic top view of the display device according to thefifth embodiment of the present disclosure corresponding to FIG. 1 .

FIG. 20 is a schematic side view of a display device according to avariant embodiment of the fifth embodiment of the present disclosure.

FIG. 21 is a schematic top view of the display device corresponding toFIG. 20 when it is unrolled.

FIG. 22 is a schematic side view of the display device corresponding toFIG. 21 when it is rolled.

FIG. 23 is a schematic bottom view corresponding to the implementationsof FIG. 20 or of FIG. 22 .

FIG. 24 is a schematic diagram corresponding to the implementations ofFIG. 20 or of FIG. 22 .

FIG. 25 is a schematic partial cross-sectional side view of the displaydevice according to the sixth embodiment of the present disclosure.

DETAILED DESCRIPTION

The present disclosure may be understood by reference to the followingdetailed description, taken in conjunction with the drawings asdescribed below. It is noted that, for purposes of illustrative clarityand being easily understood by the readers, various drawings of thisdisclosure show a portion of the touch display device, and certainelements in various drawings may not be drawn to scale. In addition, thenumber and dimension of each device shown in drawings are onlyillustrative and are not intended to limit the scope of the presentdisclosure.

Certain terms are used throughout the description and following claimsto refer to particular components. As one skilled in the art willunderstand, electronic equipment manufacturers may refer to a componentby different names. This document does not intend to distinguish betweencomponents that differ in name but not function.

In the following description and in the claims, the terms “include”,“comprise” and “have” are used in an open-ended fashion, and thus shouldbe interpreted to mean “include, but not limited to”.

When a component or a film layer is referred to as “disposed on anothercomponent or another film layer” or “electrically connected to anothercomponent or another film layer”, it may mean that the component or filmlayer is directly disposed on another component or film layer, ordirectly connected to another component or film layer, or there may beother components or film layers in between. In contrast, when acomponent is said to be “directly disposed on another component or film”or “directly connected to another component or film”, there is nocomponent or film which inserts between the two.

Although terms such as first, second, third, etc., maybe used todescribe diverse constituent elements, such constituent elements are notlimited by the terms. The terms are used only to discriminate aconstituent element from other constituent elements in thespecification. The claims may not use the same terms, but instead mayuse the terms first, second, third, etc. with respect to the order inwhich an element is claimed. Accordingly, in the following description,a first constituent element may be a second constituent element in aclaim.

The technical features in different embodiments described in thefollowing may be replaced, recombined, or mixed with one another toconstitute another embodiment without departing from the spirit of thepresent disclosure.

FIG. 1 is a schematic diagram of the display device 100 according to thefirst embodiment of the present disclosure in an unrolled state or apartially rolled state. Please refer to FIG. 1 , the display device 100includes a rollable display panel 110, an optional supporting plate 120disposed under the rollable display panel 110, and a heat dissipationsheet 140. In some embodiments, the display device 100 may alsooptionally include an electronic system 130 physically and/orelectrically connected to the rollable display panel 110, for example,to provide the rollable display panel 110 with power, or with displayinformation, or with signals, but the present disclosure is not limitedthereto. The rollable display panel 110 has two surfaces which areopposite to each other, such as a first surface 111 and a second surface112 (please see FIG. 3 ). As shown in FIG. 1 and in FIG. 3 , the firstsurface 111 may be the display side of the rollable display panel 110,and the second surface 112 may be the back side of the rollable displaypanel 110. The heat dissipation sheet 140 may be disposed on one of thetwo surfaces of the rollable display panel 110, for example, on a sideof the second surface 112, and may be rolled together with the rollabledisplay panel 110.

The rollable display panel 110 may include a flexible substrate 117(please see FIG. 3 ) and a display layer 118 (please see FIG. 3 )disposed on the flexible substrate. The flexible substrate may be atransparent or an opaque organic polymeric material, for example, mayinclude polyimide (PI), polycarbonate (PC), polyethylene terephthalate(PET), or a combination of the above, but the present disclosure is notlimited thereto. The flexible substrate may also include, for example,thin glass, or any suitable material. The display layer may include anytype of display medium, of electronic elements and/or of light-emittingelements. For example, the display medium may include a liquid crystal,fluorescence, phosphor, a light-emitting diode, other suitable displaymedia, or a combination of the above, but the present disclosure is notlimited thereto. Electronic components may include (but are not limitedto) transistors, capacitors, and/or wires. The light-emitting elementmay be an organic light-emitting diode (OLED), a micro light-emittingdiode (micro-LED), a sub-millimeter light-emitting diode (mini-LED), aquantum dot light-emitting diode (quantum dot LED, QDLED), a nano wirelight-emitting diode (nano wire LED) or a bar type LED, but the presentdisclosure is not limited thereto. The types of the light-emittingdiodes are not limited. For example, it maybe a flip chip typelight-emitting diode or a vertical type light-emitting diode, but thepresent disclosure is not limited thereto. The rollable display panel110 may generate heat when the display device 100 is in use.

The display device 100 of the present disclosure may be a flexibleelectronic device, and may be rolled with respect to a rolling axis (notshown) as the axis 109. The display device 100 of the present disclosuremay also have a rolling radius R in the rolled state, as shown in FIG. 1. The term “flexible” here refers to an electronic device which may becurved, bent, fold, rolled, flexible, stretch and/or other similardeformations, hereinafter “rollable” is used to represent theabove-mentioned deformations. The display device 100 may further includean antenna device, a sensing device or a tiling device, but the presentdisclosure is not limited thereto. The antenna device may be, forexample, a liquid crystal antenna. The tiling device may be, forexample, a display tiling device or an antenna tiling device. It shouldbe noted that the electronic device may be any combination of the above,but the present disclosure is not limited thereto.

The optional supporting plate 120 may be disposed on the second surface112 of the rollable display panel 110, and may be used to support therollable display panel 110 when necessary. The supporting plate 120 maybe a plate which has a thickness, such as an organic supporting platematerial or an inorganic supporting plate material. The organicsupporting plate material may include polyimide, and the inorganicsupporting plate material may include a metal or an alloy, such as astainless steel plate, but the present disclosure is not limitedthereto.

The electronic system 130 may include one or more electronic componentsor computing units, for example may include a battery, a system board, aprinted circuit board (PCB), a COF (chip on film), and a flexibleprinted circuit assembly, FPCA) or a combination of the above, but thepresent disclosure is not limited thereto. In the embodiment in FIG. 1 ,the electronic system 130 includes the flexible board module 1301 as anexample, but the present disclosure is not limited thereto. Theelectronic system 130 may be the signal input terminal of the displaydevice 100 to the rollable display panel 110, and may generate heat whenthe display device 100 is in use and becomes a heat source.

According to some embodiments, the heat dissipation sheet 140 may havedifferent designs according to different portions of the rollabledisplay panel 110. For example, as shown in FIG. 1 , the rollabledisplay panel 110 may include a first region 113 and a second region114. The rollable display panel 110 in the first region 113 and in thesecond region 114 may have different properties. The first region 113and the second region 114 may be different portions, and the secondregion 114 may be a part outside of the first region 113. According tosome embodiments, as shown in FIG. 1 , the first region 113 may becloser to the electronic system 130, and the second region 114 may befarther away from the electronic system 130. According to someembodiments, compared to the second region 114, the first region 113 maybe a portion with a higher temperature in the display device 100, andhave higher requirements for the heat dissipation. According to someembodiments, the first region 113 may be closer to the axis 109, and thesecond region 114 may be farther away from the axis 109.

FIG. 1 illustrates that at least a portion of the display device 100 isunrolled. As shown in FIG. 1 , a region of the rollable display panel110 surrounds the electronic system 130 by rolling. In this case, thefirst region 113 of the rollable display panel 110 may be a portion ofthe rollable display panel 110 surrounding the electronic system 130,and may be an inner circle or a first circle. The second region 114 ofthe rollable display panel 110 may be a portion other than the firstregion 113, and may be an outer circle or a second circle, surroundingthe first region 113 (the inner circle). Because the electronic system130 generates heat, the first region 113 of the rollable display panel110 surrounding the electronic system 130 is directly affected by theheat to have influences on the performance of the panel. According tosome embodiments, a heat dissipation sheet may be provided on some placeof the first region 113 of the rollable display panel 110 to be able toimprove the heat dissipation efficacy of the electronic system 130, sothat the rollable display panel 110 is less affected by the heat sourceof the electronic system 130. According to some embodiments, a heatdissipation sheet is provided in at least some region of the firstregion 113 of the rollable display panel 110.

FIG. 2 is a schematic top view of the display device 100 according tothe first embodiment of the present disclosure after being fullyunrolled, and FIG. 3 is a schematic side view corresponding to FIG. 2 .Please refer to FIG. 2 , the rollable display panel 110 may include abonding pad 150. The flexible board module 1301 of the electronic system130 of the display device 100 may be physically connected to therollable display panel 110, or the flexible board module 1301 may alsobe electrically connected to the rollable display panel 110 via thebonding pad 150. According to some embodiments, the rollable displaypanel 110 may include a peripheral area 115 and an active area 116.According to some embodiments, the peripheral area 115 may be locatedoutside of the active area 116, for example, the peripheral area 115 maysurround the active area 116. According to some embodiments, a part ofthe peripheral area 115 (the part 115A of the peripheral area as shownin FIG. 2 ) may be disposed between the active area 116 and theelectronic system 130, or a part 115A of the peripheral area 115 may becloser to the electronic system 130 than the active area 116. As shownin FIG. 2 , the first region 113 of the rollable display panel 110 maybe closer to the part 115A of the peripheral area of the electronicsystem 130, and the second region 114 may be a portion other than thefirst region 113. For example, the second region 114 may include theactive area 116 and a part 115B of the peripheral area farther away fromthe electronic system 130.

Please refer to FIG. 3 , which is a schematic side view of the displaydevice 100 in an unrolled state. The rollable display panel 110 mayinclude a flexible substrate 117 and a display layer 118 disposed on theflexible substrate 117. As shown in FIG. 3 , according to someembodiments, the heat dissipation sheet 140 may include a first portion141 and a second portion 142. The bonding pad 150 may be disposed closerto the first portion 141 and farther away from the second portion 142.In other words, the bonding pad 150 may be disposed closer to the firstportion 141 than the second portion 142. The first portion 141 may havea better heat dissipation characteristic, for example, have a betterheat dissipation characteristic than the second portion 142, but thepresent disclosure is not limited thereto. The better heat dissipationcharacteristic of the first portion 141 may be performed by means of alarger thickness, or performed by means of a material with a largerthermal conductivity, or performed by means of the two. Optionally, thefirst portion 141 and the second portion 142 of the heat dissipationsheet 140 may be interchanged. For example, the second portion 142 maybe closer to the bonding pad 150 than the first portion 141.

According to some embodiments, as shown in FIG. 3 , the first portion141 of the heat dissipation sheet 140 may be disposed corresponding tothe first region 113 of the rollable display panel 110, and the secondportion 142 of the heat dissipation sheet 140 may be disposedcorresponding to the second region 114 of the rollable display panel110, but the present disclosure is not limited thereto. For example, thefirst region 113 is closer to the electronic system 130 than the secondregion 114, and the first portion 141 may also be closer to theelectronic system 130 than the second portion 142. According to someembodiments, the first region 113 is closer to the axis 109 for rollingthan the second region 114, and the first portion 141 may be closer tothe axis 109 than the second portion 142 (shown in FIG. 1 ). Accordingto some embodiments, as shown in FIG. 1 , the first region 113 may be aninner circle so the first portion 141 also corresponds to the innercircle, and the second region 114 is an outer circle so the secondportion 142 may also correspond to the outer circle. According to someembodiments, compared to the second region 114, the first region 113 maybe closer to the heat source, and is a portion with higher heatdissipation requirements than the second region 114. For example, theheat source may include the electronic system 130. According to someembodiments, the first region 113 may be a fixed rolling region, and thesecond region 114 may be a re-rollable region (a to-and-fro rollingregion). According to some embodiments, the rollable display panel 110within the first region 113 may be fixedly accommodated in a housing,and the rollable display panel 110 within the second region 114 may bepulled out of the housing. The following embodiments respectivelydescribe implementations of the first region 113 and of the secondregion 114, and implementations of the first portion 141 and of thesecond portion 142 of the heat dissipation sheet 140.

According to some embodiments, please refer to FIG. 3 , the first region113 may be a fixed rolling region, and the second region 114 maybe ato-and-fro rolling region. The first portion 141 of the heat dissipationsheet 140 may be disposed corresponding to the first region 113, and thesecond portion 142 maybe disposed corresponding to the second region114. The design of the first portion 141 of the heat dissipation sheet140 having a larger thickness than the second portion 142 may providethe fixed rolling region with a better heat dissipation characteristic.

According to some embodiments, the boundary between the first portion141 and the second portion 142 of the heat dissipation sheet 140 may bethe same as the boundary between the first region 113 and the secondregion 114 of the rollable display panel 110. Or alternatively,according to some embodiments, the boundary between the first portion141 and the second portion 142 of the heat dissipation sheet 140 may bedifferent from the boundary between the first region 113 and the secondregion 114 of the rollable display panel 110. According to someembodiments, the first portion 141 of the heat dissipation sheet 140corresponds to the first region 113 of the rollable display panel 110,and the second portion 142 of the heat dissipation sheet 140 correspondsto the second region 114 of the rollable display panel 110. Specificallyspeaking, the first region 113 of the rollable display panel 110 may bean inner circle. For example, as shown in FIG. 3 , at least some portionof the first portion 141 of the heat dissipation sheet 140 is disposedwithin the first region 113 (the inner circle) of the rollable displaypanel 110, and at least some portion of the second portion 142 of theheat dissipation sheet 140 is disposed within the second region 114 (theouter circle) of the display panel 110. As shown in FIG. 3 , someportion of the first portion 141 of the heat dissipation sheet 140 isdisposed within the first region 113 (the inner circle) of the rollabledisplay panel 110, and other portion of the first portion 141 of theheat dissipation sheet 140 may be disposed within the second region 114.Although not shown in the figure, according to some embodiments, theentire of the first portion 141 of the heat dissipation sheet 140 may bedisposed within the first region 113. At least some portion of thesecond portion 142 of the heat dissipation sheet 140 may be disposedwithin the second region 114, and other portion of the second portion142 may be disposed within the first region 113.

According to some embodiments, the better heat dissipationcharacteristic of the first portion 141 may be performed by means of thelarger thickness T1 of the first portion 141. For example, the firstregion 113 of the rollable display panel 110 is closer to the electronicsystem 130 and may be a region requiring high heat dissipation ability.FIG. 3 illustrates that the first portion 141 may correspond to theregion requiring high heat dissipation ability (the first region 113),and the thickness T1 of the first portion 141 may be greater than thethickness T2 of the second portion 142. For example, the thickness T1 ofthe first portion 141 is larger than the thickness T2 so that the firstportion 141 disposed on the heat dissipation sheet 140 has a better heatdissipation characteristic. The larger thickness T1 of the first portion141 is beneficial to quickly dissipate the heat of the electronic system130 to the entire first portion 141 and then to the second portion 142.The thickness T1 of the first portion 141 is thicker so that sufficientheat energy maybe smoothly transferred to the heat dissipation sheet 140to make the heat dissipation sheet 140 have better utilizationefficiency.

According to some embodiments, a better heat dissipation characteristicof the first portion 141 may be performed by means of a material of thefirst portion 141 with a greater thermal conductivity. For example, thethermal conductivity of a material of the first portion 141 may begreater than the thermal conductivity of a material of the secondportion 142. Optionally, the thickness of the first portion 141 and ofthe second portion 142 may be the same or different as needed. FIG. 4 isa schematic side view of a variant embodiment corresponding to FIG. 2 .The heat dissipation sheet 140 may have a thermal conductivity greaterthan 200 W/mK. FIG. 4 illustrates that the first portion 141 maycorrespond to a portion requiring high heat dissipation ability (thefirst region 113), and the thermal conductivity of the first portion 141may be greater than the thermal conductivity of the second portion 142.The suitable materials of the heat dissipation sheet 140 may includediamond, silver, copper, gold, aluminum, graphite, and a combinationthereof, but the present disclosure is not limited thereto. If the firstportion 141 of the heat dissipation sheet 140 uses a material with agreater thermal conductivity, it may be beneficial to quickly dissipatethe heat of the electronic system 130 to the first portion 141.According to some embodiments, if the heat dissipation sheet 140includes a composite material, the thermal conductivity of the heatdissipation sheet 140 may reside in the thermal conductivity of thematerial with the greatest thermal conductivity. The thermalconductivity may be measured by looking up the tables to obtain thethermal conductivity corresponding to each component (or element) afteranalyzing the various components (or elements) of a heat dissipationsheet. Or alternatively, it may also be obtained by measuring a heatdissipation sheet with a thermal conductivity analyzer. According tosome embodiments, the better heat dissipation characteristic of thefirst portion 141 may also be performed by means of the greater thermalconductivity of the first portion 141 to go with a larger thickness T1together.

Please refer to FIG. 4 again. In addition to the electronic system 130physically connected to the rollable display panel 110, the electronicsystem 130 may also be physically connected to the heat dissipationsheet 140 by means of extension. For example, the electronic system 130may also be bent backwards extending toward the back side of therollable display panel 110 by rolling so that the two end points of theelectronic system 130 may be respectively physically connected to therollable display panel 110 and to the first portion 141 of the heatdissipation sheet 140. Such a configuration is beneficial to dissipatethe heat of the electronic system 130 directly and quickly to the firstportion 141.

FIG. 5 is a schematic diagram of the display device 100 in a partiallyrolled state according to the second embodiment of the presentdisclosure. According to the display device 100 of the second embodimentof the present disclosure, in a rolled state or a half-rolled state, itis possible that a second circle 113′ rolls to surround the first region113 serving as the first circle. A rolled state may be a state which hascurvature of most of the rollable display panel 110 or of the heatdissipation sheet 140. The region of the rollable display panel 110closer to the axis 109 may be referred to as a fixed rolling region ofthe rollable display panel 110. In some embodiments, a fixed rollingregion may be, for example, the first region 113 corresponding to therollable display panel 110. Whether it is in a rolled state or in anunrolled state, the fixed rolling region is kept rolled, that is, toform the first circle surrounding the electronic system 130. The fixedrolling region may not have a display function or provide no display.The region other than the fixed rolling region of the rollable displaypanel 110 may be referred to as a to-and-fro rolling region of therollable display panel 110. The to-and-fro rolling region may, forexample, include the second circle 113′ and correspond to the secondregion 114. When the rollable display panel 110 is in an unrolled state,the to-and-fro rolling region is generally unrolled to become a plane(as shown in FIG. 1 ).

FIG. 6 is a schematic side view of an implementation corresponding toFIG. 2 . According to some embodiments, the active area 116 of therollable display panel 110 may be designed in some region after thefirst circle. In details, the second region 114 of the rollable displaypanel 110 may include the active area 116, and the first region 113 ofthe rollable display panel 110 may include a part 115A of the peripheralarea close to the electronic system 130. As shown in FIG. 6 , the firstportion 141 of the heat dissipation sheet 140 corresponds to the firstregion 113 of the rollable display panel 110, and the second portion 142of the heat dissipation sheet 140 corresponds to the second region 114of the rollable display panel 110. For example, at least some portion ofthe first portion 141 of the heat dissipation sheet 140 may be disposedwithin the first region 113, and at least some portion of the secondportion 142 of the heat dissipation sheet 140 may be disposed within thesecond region 114 (the active region 116). Such a design is beneficialto reduce the probability of display abnormality of the display device100 due to heat, and thus may increase the reliability of the rollabledisplay device 100. Specifically speaking, the first region 113 of therollable display panel 110 may be the part 115A of the peripheral areaclose to the electronic system 130. For example, as shown in FIG. 6 ,according to some embodiments, all of the first portion 141 of the heatdissipation sheet 140 may be disposed within the first region 113 (thepart 115A of the peripheral area). At least some portion of the secondportion 142 of the heat dissipation sheet 140 may be disposed within thesecond region 114 (the active area 116), and other portion of the secondportion 142 may be disposed within the first region 113. Although notshown in the figure, according to some embodiments, a portion of thefirst portion 141 of the heat dissipation sheet 140 is disposed withinthe first region 113 (the part 115A of the peripheral area) of therollable display panel 110, and other portion of the first portion 141is disposed within the second region 114 (the active area 116) of therollable display panel 110, and all of the second portion 142 of theheat dissipation sheet 140 is disposed within the second region 114 (theactive area 116) of the rollable display panel 110.

According to some embodiments, the surface of the heat dissipation sheet140 may be provided with an opening 240. The opening 240 may be a recessand/or a trench. FIG. 7 is a schematic side view of another variantimplementation corresponding to FIG. 2 . The thickness of the heatdissipation sheet 140 in the fixed rolling region (the first region 113)may be T3, and the thickness of the heat dissipation sheet 140 in theto-and-fro rolling region (the second region 114) has a smallerthickness. The heat dissipation sheet 140 may include at least onerecess 143 so that a protrusion 145 of the heat dissipation sheet 140may be formed between the recesses 143. The recess 143 may be recessedinto the surface 140S of the heat dissipation sheet 140, but the recess143 may not expose the rollable display panel 110 or the supportingplate 120 on the other side of the heat dissipation sheet 140. In otherwords, the recess 143 may not penetrate the heat dissipation sheet 140.By providing at least one recess 143 on the heat dissipation sheet 140,the average thickness of the heat dissipation sheet 140 may be reduced.The heat-dissipating surface area of the heat dissipation sheet 140 mayalso be increased, and/or the flexibility of the to-and-fro rollingregion may also be increased to facilitate to increase the reliabilityof the rollable display panel 110 in the to-and-fro rolling region (thesecond region 114). The calculation method of the average thickness isshown in FIG. 9 and in the corresponding descriptions below.

FIG. 8 is a schematic side view of another variant implementationcorresponding to FIG. 2 . The heat dissipation sheet 140 may include atleast one opening 240 (a trench 144). The trench 144 may be recessedinto the surface 140S of the heat dissipation sheet 140, and the bottomof the trench 144 may also expose some part of the rollable displaypanel 110 or of the supporting plate 120. FIG. 8 illustrates that thetrench 144 may expose some part of the supporting plate 120. In otherwords, the trench 144 may penetrate the heat dissipation sheet 140 sothat a protrusion 145 of the heat dissipation sheet 140 may be formedbetween the trenches 144. With the design of the opening 240, theaverage thickness of the heat dissipation sheet 140 may be reduced. Inaddition, the heat-dissipating surface area of the heat dissipationsheet 140 may also be increased, and/or the flexibility of theto-and-fro rolling region may also be increased, to more beneficiallyincrease the reliability of the rollable display panel 110 in theto-and-fro rolling region.

FIG. 9 is a schematic bottom view according to an implementation of thepresent disclosure. According to some embodiments, as shown in FIG. 9 ,the heat dissipation sheet 140 may include a plurality of openings 240.The opening 240 may be a recess 143, a trench 144, or a combinationthereof. The extending direction D11 of the recess 143 or of the trench144 may be perpendicular to the unrolling direction D2 of the displaydevice 100. As shown in FIG. 10 , the extending direction D12 of therecess 143 or of the trench 144 may be designed to be parallel to theunrolling direction D2 of the display device 100. The calculation methodof the average thickness of the heat dissipation sheet 140 is asfollows. Please refer to the method shown in FIG. 9 . For example, thewidth of the heat dissipation sheet 140 is W, and the width W maybe thewidth in the direction perpendicular to the unrolling direction D2 ofthe display device 100. The width of the heat dissipation sheet 140 maybe divided into four quarters, such as 0.25 W, 0.5 W, 0.75 W are taken,and the total thicknesses of 10 points along each horizontal line arerespectively measured and then averaged to get the average thickness ofthe heat dissipation sheet 140, but the present disclosure is notlimited thereto. If the designs of the first portion 141 are differentfrom the designs of the second portion 142 of the heat dissipation sheet140, the average thicknesses of the first portion 141 and of the secondportion 142 may be calculated separately. According to some embodiments,the first portion 141 of the heat dissipation sheet 140 may be providedcorresponding to the first region 113, and the second portion 142 may beprovided corresponding to the second region 114. The thickness of thefirst portion 141 in the first region 113 may be measured, and thethickness of the second portion 142 in the second region 114 maybemeasured. The thicknesses of the first portion 141 and of the secondportion 142 of the heat dissipation sheet 140 in the first region 113and in the second region 114 may be respectively measured by referringto the above-mentioned method of dividing the width of the heatdissipation sheet 140 into four quarters. For every 10 points taken in aportion, the distance between two adjacent points may be equal. In otherwords, there may be 10 points of the same pitch. However, themeasurement of the average thickness is not limited thereto. Accordingto some embodiments, two points in one portion may also be taken for thethickness measurement. According to some embodiments, samples of theheat dissipation sheet 140 of the same size, for example, a sample of 1cm², may be taken respectively out of the first region 113 and out ofthe second region 114 of the rollable display panel 110 to be subjectedto the measurement of the thickness. According to some embodiments, thethickness of the heat dissipation sheet 140 may not be limited to theaverage thickness, and may also be the thickness at a specific location.

FIG. 11 is a schematic bottom view of an implementation according to thepresent disclosure. In another implementation of the present disclosure,as shown in FIG. 11 , the recesses 143 or the trenches 144 may form anuneven distribution along the unrolling direction D2 of the displaydevice 100, so that the average thickness of different portions may bedifferent. For example, if the flexibility requirement of the firstregion 113 is greater than that of the second region 114, the regioncloser to the first region 113 of the electronic system 130 may beoptionally provided with more recesses 143 or trenches 144 as needed,that is, the distribution density of the recesses 143 or of the trenches144 may be larger, where the distribution density may represent thenumber of the recesses 143 or of the trenches 144 per unit area of theheat dissipation sheet 140, or the area occupied by the recesses 143 orby the trenches 144 per unit area of the heat dissipation sheet 140, butthe present disclosure is not limited thereto.

FIG. 12 illustrates a schematic side view of a variant implementation ofthe heat dissipation sheet 140. The heat dissipation sheet 140 may haveone or more protrusions 145. For example, the heat dissipation sheet 140may include a first portion 141 and a second portion 142, and aplurality of protrusions 145 may be provided in the to-and-fro rollingregion corresponding to the second portion 142. The density of theprotrusions 145 may be optionally different, but the present disclosureis not limited thereto. The protruding portion 145 may increase theheat-dissipating surface area of the heat dissipation sheet 140, or mayalso increase the flexibility of the to-and-fro rolling region, therebyfacilitating to increase the reliability of the rollable display panel110 in the to-and-fro rolling region. The density of the protrusions 145may adjust the rolling radius R of the rollable display panel 110.

FIG. 13 is a schematic side view of a variant implementation of the heatdissipation sheet 140. The thickness T5 of the first portion 141 of theheat dissipation sheet 140 may be greater than the thickness T6 of thesecond portion 142. The first portion 141 and the second portion 142maybe evenly provided with the protrusions 145 and with the openings240, but the present disclosure is not limited thereto. The greaterthickness of the fixed rolling region may make sufficient heat energysmoothly dissipated to all the protrusions 145, so that all theprotrusions 145 are most efficiently used.

FIG. 14 is a schematic side view of a variant implementation of the heatdissipation sheet 140. One or more protrusions 145 and openings 240 maybe evenly provided in the second portion 142 of the heat dissipationsheet 140. The thickness T5 of the first portion 141 of the heatdissipation sheet 140 may be greater than the thickness T6 of the secondportion 142, but the present disclosure is not limited thereto. Thethickness design of this variant implementation reduces from the firstportion 141 which is closer to the electronic system to the secondportion 142, so that the heat dissipation sheet 140 may absorb enoughheat from the electronic system part to quickly dissipate it to thesurrounding thinner portion.

FIG. 15 is a schematic side view of the display device 100 according tothe third embodiment of the present disclosure. If it is needed toincrease the heat dissipation characteristic of the display device 100,it may also be performed by means of deepening a trench 121 of the heatdissipation sheet 140 into the optional supporting plate 120. Forexample, the heat dissipation sheet 140 may include a first portion 141disposed in the first region 113 and a second portion 142 disposed inthe second region 114. There may be at least one trench 121 in theoptional supporting plate 120. At least one trench 121 of the supportingplate 120 may be recessed into the surface 120S of the supporting plate120, and the trench 121 may further expose a region of the rollabledisplay panel 110. The trench 121 goes deep into the surface 120S of thesupporting plate 120, or the supporting plate 120 may also be designedto be thinner to increase the flexibility of the to-and-fro rollingregion when being frequent rolled, and to be beneficial to increase thereliability of the rollable display panel 110 in the to-and-fro rollingregion. The location of the trench 144 of the heat dissipation sheet 140may coincide with the location of the hole of the trench 121 of thesupporting plate 120 to reduce the risk of peeling off of the two layerswhen the rollable display panel 110 is rolled to maintain the adhesionbetween the two layers. According to some embodiments, an auxiliary heatdissipation material 122 may also be used to fill the trench 121 and/orthe trench 144. For example, the auxiliary heat dissipation material 122may fill some of the trenches 121 and/or of the trenches 144, or theauxiliary heat dissipation material 122 may partially fill the trenches124 and/or the trenches 144 without filling up the trenches 121 and/ortrenches 144, but the present disclosure is not limited thereto. Theauxiliary heat dissipation material 122 may be thermal grease, thermalgel, or a combination thereof, but the present disclosure is not limitedthereto.

FIG. 16 is a schematic diagram of the display device 100 in an unrolledstate according to the fourth embodiment of the present disclosure.According to some embodiments, in FIG. 16 , at least some of therollable display panel 110 is unrolled. The display device 100 of thefourth embodiment of the present disclosure may further include ahousing 160. In a rolled state, the housing 160 may accommodate therollable display panel 110 and the heat dissipation sheet 140. Accordingto some embodiments, the housing 160 may accommodate the rollabledisplay panel 110, the supporting plate 120, and an electronic system(not shown). When the housing 160 rotates in the D3 direction, therollable display panel 110 may be pulled out from the housing 160together with the heat dissipation sheet 140 to obtain the unrolledstate of the display device 100. Please refer to the above, anelectronic system (not shown) and/or the rollable display panel 110 maygenerate heat when the display device 100 is in use. According to thedisplay device 100 of the fourth embodiment of the present disclosure,the display device 100 includes a housing 160, and at least some of theheat generated by the rollable display panel 110 may be dissipated bythe housing 160 via the heat dissipation sheet 140. In other words,according to some embodiments, the heat-dissipating direction of theheat generated by the rollable display panel 110 may be: first throughthe heat dissipation sheet, and then through the housing. Theoretically,the direction of heat transfer is from high temperature to lowtemperature. Therefore, by respectively detecting the surfacetemperatures of the rollable display panel 110, of the heat dissipationsheet 140, and of the housing 160, the heat transfer direction may beidentified from the temperature gradient. According to some embodiments,the detection location of the surface temperature of the rollabledisplay panel 110 may be a location closer to the bonding pad 150.According to some embodiments, the detection location of the surfacetemperature of the rollable display panel 110 may be a location closerto the rolling axis. According to some embodiments, the detectionlocation of the surface temperature of the rollable display panel 110may be the first portion of the rollable display panel 110. According tosome embodiments, the detection location of the surface temperature ofthe rollable display panel 110 may be a location corresponding to thefirst portion 141 of the heat dissipation sheet 140. According to someembodiments, the detection location of the surface temperature of therollable display panel 110 may correspond to a location closer to thefirst portion 141 of the heat dissipation sheet 140.

Please refer to FIG. 3 together with FIG. 16 . FIG. 3 shows the rollabledisplay panel 110 in a fully unrolled state, and FIG. 16 shows someregion of the rollable display panel 110 in a rolled state. Some regionof the rollable display panel 110 may be rolled to be accommodated in ahousing 160. According to some embodiments, the first region 113 of therollable display panel 110 may be an interior housing region, that is,the second region 114 may be an exterior housing region. The firstportion 141 of the heat dissipation sheet 140 may be disposedcorresponding to the first region 113, and the second portion 142 may bedisposed corresponding to the second region 114. In other words, theinterior housing region may be the portion of the heat dissipation sheet140 which is accommodated in the housing 160 when the display device 100is in the fully unrolled state, and the exterior housing region may bethe portion of the heat dissipation sheet 140 which is not accommodatedin the housing 160 when the display device 100 is in the fully unrolledstate. Compared with the exterior housing region, the interior housingregion may have a better heat dissipation characteristic. The betterheat dissipation of the interior housing region may be performed bymeans of a larger thickness T1 of the heat dissipation sheet 140 in theinterior housing region (the first region 113). For example, thethickness T1 of the interior housing region may be greater than thethickness T2 of the exterior housing region (the second region 114).Please refer to the aforementioned descriptions for the details of theheat dissipation sheet 140 with a larger thickness T1 in the interiorhousing region.

FIG. 17 is a schematic diagram of a variant embodiment of the displaydevice 100 according to the fourth embodiment of the present disclosure.As shown in FIG. 16 or in FIG. 17 , ventilation holes 163 may beprovided in the housing 160 to increase the heat dissipation ability ofthe housing. The ventilation holes 163 on the housing 160 may include aplurality of holes as shown in FIG. 16 , or concentric rings as shown inFIG. 17 , but the present disclosure is not limited thereto.

FIG. 18 is a schematic diagram of another variant embodiment of thedisplay device 100 according to the fourth embodiment of the presentdisclosure. According to some embodiments, ventilation blades 164 may beprovided in the housing 160 to increase the heat dissipation ability ofthe housing 160. For example, the ventilation blades 164 in the housing160 may facilitate to generate air turbulence to increase the heatdissipation ability of the housing 160 when the heat dissipation sheet140 is retracted into the housing 160 or pulled out of the housing 160to rotate in the D3 direction, but the present disclosure is not limitedthereto.

FIG. 19 is a schematic top view of the display device 100 according tothe fifth embodiment of the present disclosure corresponding to FIG. 1 .FIG. 19 shows the heat dissipation sheet 140 of the display device 100to correspond to the size of the rolling radius R in the rolled state ofFIG. 1 . For example, according to some embodiments, the width of theheat dissipation sheet 140 may be greater than 0.5 W if the width of therollable display panel 110 is W, but the present disclosure is notlimited thereto. The length of the heat dissipation sheet 140 may begreater than 2πR when the rolling radius of the heat dissipation sheet140 in the rolled state is R. A portion of the heat dissipation sheet140 may still be exposed to the outside when the heat dissipation sheet140 is in the rolled state corresponding to FIG. 1 as the length of theheat dissipation sheet 140 is greater than 2πR to facilitate to increasethe heat dissipation ability of the heat dissipation sheet 140.

FIG. 20 is a schematic side view of a display device 101 according to avariant embodiment of the fifth embodiment of the present disclosure.According to some embodiments, as shown in FIG. 20 , the display device100 may have more than one rollable portion, such as a first rollableportion 105 and a second rollable portion 106, and the first rollableportion 105 and the second rollable portion 106 maybe respectivelydisposed on the opposite sides of the rollable display panel 110. Thefirst rollable portion 105 and the second rollable portion 106 mayrespectively have a rolling radius R in a rolled state. Disposed betweenthe first rollable portion 105 and the second rollable portion 106,there may be a display portion 107 of the rollable display panel 110. Atleast one of the first rollable portion 105 and the second rollableportion 106 may include one or more electronic components or computingunits, for example include a bonding pad (not shown), a battery (notshown), a system board (not shown), a printed circuit board (PCB), achip on film (COF), a flexible printed circuit assembly (FPCA) (notshown) or a combination of the above, but the present disclosure is notlimited thereto. At least one of the first rollable portion 105 and thesecond rollable portion 106 may include an electronic system (not shown)of the display device 100, and a heat dissipation sheet 140 may beprovided between the electronic system (not shown) and the rollabledisplay panel 110, but the present disclosure is not limited thereto. Inthis variant embodiment, the electronic system 130 may also be providedin the display portion 107 to be physically and/or electricallyconnected to the heat dissipation sheet 140 in the display portion 107.Therefore, the electronic system 130 is still exposed when the rollabledisplay panel 110 is rolled to facilitate to improve the heatdissipation of the rollable display device 100. That is to say, theelectronic system 130 physically and/or electrically connected to theheat dissipation sheet 140 in the display portion may quickly dissipateheat to everywhere through the heat dissipation sheet 140 whether therollable display panel 110 is rolled or unrolled, for example, toquickly dissipate heat to the rollable display panel 110 in the displayportion 107 and/or to quickly dissipate heat to at least one of thefirst rollable portion 105 and the second rollable portion 106 tofacilitate the display device 100 to have a better heat dissipationcharacteristic, but the present disclosure is not limited thereto.

FIG. 21 is a schematic top view of the display device 101 correspondingto FIG. 20 when it is unrolled. The width of the heat dissipation sheet140 may be greater than 0.5 W if the width of the rollable display panel110 is W, but the present disclosure is not limited thereto. The lengthof the heat dissipation sheet 140 may be greater than L if the length ofthe rollable display panel 110 in the display portion is L, so that theheat dissipation sheet 140 may extend into at least one of the firstrollable portion 105 and the second rollable portion 106 to facilitateto increase the heat dissipation ability of the heat dissipation sheet140.

FIG. 22 is a schematic side view of the display device 101 correspondingto FIG. 21 when it is rolled. The heat dissipation sheet 140 in at leastone of the first rollable portion 105 and the second rollable portion106 may include at least one of the recess 143 and the trench 144, andthe quantity of the recess 143 and the trench 144 may be optional asneeded. Please refer to the aforementioned descriptions for the detailsand advantages of the recess 143 and the trench 144. FIG. 22 illustratesthat the first rollable portion 105 and the second rollable portion 106may include recesses 143 and the trenches 144, but the presentdisclosure is not limited thereto.

FIG. 23 is a schematic bottom view corresponding to the implementationsof FIG. 20 or of FIG. 22 . The heat dissipation sheet 140 may include arecess 143 and a trench 144, and the recess 143 and the trench 144 maybedisposed in at least one of the first rollable portion 105, the secondrollable portion 106 and the display portion 107. FIG. 23 shows that therecesses 143 and the trenches 144 may be provided in the first rollableportion 105, in the second rollable portion 106 and in the displayportion 107, but the present disclosure is not limited thereto.

FIG. 24 is a schematic diagram corresponding to the implementations ofFIG. 20 or of FIG. 22 . The electronic system 130 may be provided underthe rollable display panel 110, and the electronic system 130 may alsobe provided between the first rollable portion 105 and the secondrollable portion 106, but the electronic system 130 is exposed tofacilitate to increase the heat dissipation ability of the displaydevice 101.

FIG. 25 is a schematic partial cross-sectional side view of the displaydevice 100 according to the sixth embodiment of the present disclosure.The display device 100 of the sixth embodiment of the present disclosuremay include a heat dissipation frame 170 to facilitate the heatdissipation along the planar direction and homogenizes hot spots. Forexample, the heat dissipation frame 170 may be disposed under the heatdissipation sheet 140, so that the heat dissipation sheet 140 may bedisposed between the heat dissipation frame 170 and the rollable displaypanel 110 or the optional supporting plate 120. For example, the heatdissipation frame 170 maybe disposed in the first region 113 or disposedadjacent to the axis 109, but the present disclosure is not limitedthereto. For example, according to some embodiments, the heatdissipation frame 170 may not be rolled out together with the heatdissipation sheet 140 and not with the rollable display panel 110 whenthe heat dissipation sheet 140 is rolled out together with the rollabledisplay panel 110. For example, taking FIG. 16 as an example, the heatdissipation frame (not shown) may not be rolled out together with theheat dissipation sheet 140 and not with the rollable display panel 110to be accommodated in the housing 160, but the present disclosure is notlimited thereto. The heat dissipation frame 170 may include a strongmaterial, such as glass or plastic, or a material with a high thermalconductivity, such as a metal or an alloy, for example analuminum-magnesium alloy, but the present disclosure is not limitedthereto.

According to the rollable display device of the embodiments of thepresent disclosure, the installation of the heat dissipation sheetfacilitates the thermal conduction and/or dissipation of the heatgenerated by the rollable display panel, thereby improving the heatdissipation quality of the rollable display device to enhance thereliability of the rollable display device.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the disclosure. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. A display device, comprising: a rollable displaypanel having two surfaces opposed to each other; and a heat dissipationsheet disposed on one of the two surfaces of the display panel and beingrollable together with the rollable display panel, wherein the heatdissipation sheet has a thermal conductivity greater than 200 W/mK. 2.The display device according to claim 1, wherein the heat dissipationsheet comprises a first portion and a second portion, wherein the firstportion has a better heat dissipation characteristic.
 3. The displaydevice according to claim 2, wherein the better heat dissipationcharacteristic is performed by means of a greater thickness.
 4. Thedisplay device according to claim 2, wherein the better heat dissipationcharacteristic is performed by means of a material with a greaterthermal conductivity.
 5. The display device according to claim 2,wherein a bonding pad of the rollable display panel is disposed closerto the first portion than the second portion.
 6. The display deviceaccording to claim 1, further comprising a housing to accommodate therollable display panel and the heat dissipation sheet, from which therollable display panel is rolled out together with the heat dissipationsheet.
 7. The display device according to claim 6, wherein at least someheat generated by the rollable display panel is dissipated through theheat dissipation sheet and then through the housing.
 8. The displaydevice according to claim 6, wherein a first region of the rollabledisplay panel is fixedly accommodated in the housing.
 9. The displaydevice according to claim 8, wherein a second region of the rollabledisplay panel is pulled out of the housing.
 10. The display deviceaccording to claim 2, further comprising: an electronic systemphysically or electrically connected to the rollable display panel. 11.The display device according to claim 10, wherein the first portion iscloser to the electronic system than the second portion.
 12. The displaydevice according to claim 10, wherein the first portion quicklydissipates heat from the electronic system to the first portion and thento the second portion.
 13. The display device according to claim 10,wherein a first region of the rollable display panel is closer to theelectronic system than a second region of the rollable display panel.14. The display device according to claim 10, wherein the first regionsurrounds the electronic system.
 15. The display device according toclaim 1, wherein a surface of the heat dissipation sheet is providedwith an opening.
 16. The display device according to claim 15, whereinthe opening comprises a recess, a trench or a combination thereof. 17.The display device according to claim 1, further comprising: a firstrollable portion and a second rollable portion.
 18. The display deviceaccording to claim 17, wherein a display portion of the rollable displaypanel is disposed between the first rollable portion and the secondrollable portion.
 19. The display device according to claim 1, furthercomprising: a supporting plate disposed under the rollable display panelto support the rollable display panel.
 20. The display device accordingto claim 1, further comprising: a heat dissipation frame so that theheat dissipation sheet is disposed between the heat dissipation frameand the rollable display panel.